Following the leaks about NSA surveillance, people demanded information about the scope and scale of the US government's data collection. In response, the administration offered internet companies a deal: they could publish the number of secret national security requests, but only if it was aggregated with data about non-secret, criminal requests.

Facebook, Apple, Microsoft, and Yahoo! immediately accepted and published aggregate data. But Google rejected the offer, stating that "lumping the two categories together would be a step back for users".

Google is right. Americans are understandably concerned that their digital privacy may be eroded through the government's ham-handed approach to foreign surveillance. But fixating on the accidental collection of domestic communications during foreign surveillance risks ignoring the ways that the US government legally and intentionally surveils the digital communications of its citizens. We must be careful that, in our rush to answer questions about Prism, we don't endanger the gains we have made over the past few years in understanding our domestic surveillance apparatus.

This week, leading technology companies, including Prism participants Facebook, Google, Apple, and Microsoft, issued a joint letter with prominent members of civil society asking the US government to allow them to publish summary statistics about national security requests for user data separate from their existing reports about domestic criminal requests. It's a critical step.

An outdated law called the Electronic Communications Privacy Act (ECPA) gives the government broad powers to request data on US citizens stored by companies like Google, Facebook, Microsoft, and Twitter. Using a subpoena, a law enforcement agency can obtain your name, address, IP addresses, data about when you sign on and off, and your payment processing information, all without any court intervention. And in some circumstances, simply by notifying the target of the investigation, the government can use a subpoena to collect opened emails and unopened emails stored for longer than 180 days (and agencies can postpone that notice in some circumstances). The government doesn't need to accidentally slurp up domestic data through Prism when it is so easy for them to legally and intentionally collect the digital data of its citizens.

Google and Twitter have been pioneers in educating consumers about the scope and scale of the US domestic criminal surveillance state. Starting in 2009, Google became the first internet company to begin publishing statistics about government requests for user data. In 2012, Twitter followed suit. And over the past few months, seven other tech companies, including Microsoft and Dropbox, have joined in publishing transparency reports.

Although informative about our domestic criminal surveillance state, these reports told us very little about secretive national security surveillance. And make no mistake, we need transparency reports on national security surveillance just like the ones Google, Twitter, and others release on domestic surveillance.

That said, the Faustian deal the administration offered for aggregate reporting handicaps all transparency reporting while failing to provide useful information about the secret surveillance state. Facebook, Apple, and Yahoo! have never published transparency reports before, so when Facebook accepted the deal and then reported that they received 9,000 to 10,000 requests in the six-month period ending on 31 December, we have no clue whether 10% or 90% of those are national security requests because we have no baseline for comparison. And that's why it is likely the government offered this deal: it does not reveal very much, other than the vague reassurance that the number of requests are in the thousands instead of millions.

But the deal gets worse. By combining domestic and national security figures, companies may be committing themselves to publishing less transparent transparency reports than they currently do. The perfect illustration is the situation Microsoft now finds itself in as the only company to accept the deal that has previously released a transparency report. According to their pre-deal transparency report, Microsoft received 12,227 criminal requests on 29,379 accounts in the United States in 2012. As a rough estimate, we can assume that during the six-month period ending December 31, 2012, the totals were 6,114 requests on 14,690 accounts. After accepting the deal, Microsoft revealed that during that same six-month period, they received between 6,000 and 7,000 requests on 31,000 to 32,000 accounts when aggregating both secret national security requests and domestic criminal requests.

Simply by subtracting, we can estimate that Microsoft received between zero and 886 national security requests covering 16,310 to 17,310 accounts. If the government's goal is to obscure national security requests, companies are going to need to be even vaguer and less transparent than Microsoft was in its last report. And including more specific data such as the number of warrants and subpoenas may become impossible.

That is why Google called the administration's offer a step backwards and the letter the technology companies sent this week is so important. We need greater transparency into the US government's secret surveillance programs. In getting that transparency, however, we shouldn't sacrifice transparency about the government's non-secret surveillance programs. After all, if our estimates are correct, national security surveillance accounted for only about 13% of the total requests Microsoft received and 54% of the total accounts surveilled. That means that non-secret criminal surveillance of Americans is as pervasive, if not more so, than the secret national security surveillance.